What made Cnut ‘Great’? The short answer is that he was the big winner at the time when the Viking Age turned into Game of Thrones. Cnut was the son of Swen Forkbeard, the son of Harald Bluetooth. On the larger of the two runic stones he had cut at Jelling in Jutland, Cnut’s grandfather described himself as the man who ‘won the whole of Denmark for himself, and Norway, and made the Danes Christian’. All three claims are dubious. The conversion of Denmark does not seem to have made the Danes notably or universally Christian, Norway remained ungovernable by anyone and Harald’s rule of Denmark was terminated by Swen’s rebellion.

Not long after Harald’s death in the 980s, however, it seems to have dawned on ambitious Scandinavian kings that the real jewel in the crown was England. In 991, defeat at the Battle of Maldon – an event commemorated in a famous Old English poem – led King